Observations of Acoustic Interruptions Versus Ambient Sound Levels With Perceived Sleep Quality During Critical Illness

Abstract

ICUs are loud and there is an association between ambient sound and worsened sleep quality. In contrast to ambient sound, short acoustic interruptions or sound spikes—for example, brief alarm tones—cause arousal from sleep in healthy patients, but remain understudied in critically ill patients, despite the observed frequency of ICU alarms. We collected greater than 2.3 million values of ambient sound (every second) among 14 patients in the ICU over a median of two nights (interquartile range, 1–2) each. We identified brief acoustic interruptions/sound spikes—increases of greater than or equal to 20 dB above ambient—over 1 second. Patients experienced a median of five interruptions greater than or equal to 20 dB (interquartile range, 2–12) per night. Each interruption was associated with a 1-point decrease in patient reported quality of sleep, as assessed by the Richards Campbell Sleep Questionnaire. Our observations suggest a possible relationship between acoustic interruptions and worsened perceived sleep.

Perceived sounds and their reported level of disturbance in intensive care units: A multinational survey among healthcare professionals

“…The sound pressure levels, commonly referred to as simply the sound levels, in intensive care units (ICUs) far exceed the public health recommendations of 35-40 dBA [1][2][3][4][5][6][7]. Not only is this detrimental to patients exposed to noise while hospitalised, but it also affects healthcare professionals working in hospitals [8][9][10][11][12][13][14][15][16][17]. Among other effects, acute exposure to high noise levels has also been found to cause tachycardia, while chronic exposure has been linked to hypertension, heart disease, and stroke [18,19].…”

Evaluation of the sensory environment in a large tertiary ICU

“…However, the threshold for waking may increase when patients are continually exposed to a noisy environment [ 58 ]. Sound variability, AIs, and peak sound levels are therefore more likely to negatively impact sleep than ambient sound, as our brains are better at ignoring continuous sound than sudden changes [ 23 , 49 , 59 ]. This occurred frequently and was more common at night (when the ambient sound was lower).…”